Many compounds for use as deposit control additives for fuel oils such as gasoline and gas oil, have been disclosed hitherto.
Examples of such compounds include polyoxyalkylene carbamates (JP-A-53-2505 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), JP-A-55-25489, and U.S. Pat. No. 4,778,481), alkylene oxide adducts of reaction products of higher carboxylic acids with polyamines (JP-A-61-113691), polyoxyalkylenealkylamines (JP-A-62-68891), reaction products of maleic anhydride with polyamines or polyether polyamines (JP-A-62-20590), and polybutylamines (JP-A-62-241992).
Deposit control additives for fuel oils are required not only to show excellent detergent dispersiveness but also to have the properties of not forming itself into sludge and of being easily dissolved in fuel oils. It is preferable that deposit control additives be produced without use of highly toxic chemicals such as phosgene.
The conventional deposit control additives for fuel oils, however, have not fully satisfied these requirements.